As display devices usable for electric appliances and electronic devices, a liquid crystal display device using an electro-optical effect of a liquid crystal material and an organic EL (electroluminescence) display device including an organic electroluminescence (EL) element have been developed and put into actual products.
Especially, an organic EL element, when being used as a display element, has a feature of realizing a wide viewing angle and highly precise display, and also of being allowed to be located on a flexible substrate. Japanese Laid-Open Patent Publication No. 2011-209405 discloses a display device including a flexible substrate that is foldable at a wiring portion connecting a pixel array portion and a peripheral circuit portion to each other. Such a structure allows a bezel of the display device to be narrower, which decreases the size of the display device.